Back ground: Synthetic bone substitutes have been advanced, and researches are developed to more effective biomaterials with promising ability to reconstruct lost bone structure. Tricalcium phosphate biomaterials and white Portland cement are among them. The aim of the current study is to assess the effect of β-tricalcium phosphate versus white Portland cement in surgically mandibular bone defect dogs. Material and methods:Six adult dogs were used. The anaesthesia was conducted by iv injection of thiopental sodium 20mg/kg.b.wt. and maintained using (atropine 0.04 mg/kg b.wt., xylazine 1mg/kg.b.wt. and diazepam 1mg/kg.b.wt.in saline iv drop by drop infusion ), three critical size defects were designed at the buccal side of the mandible. The defects were 5 cm apart from each other. One defects filled with sterile white Portland cement, the middle defect filled with β-tricalcium phosphate and the later one was left empty. The dogs were euthanized at the end of 1 and 8 week postoperatively respectively. The specimens were prepared for light microscope using H&E and Masson Tri-chrome staining. Results: The experimental sides of all periods revealed increasing the amount of new bone trabeculae extended from original bone towards the center of the defect with both white Portland cement & β-tricalcium phosphate. While, the control sides displayed few new bone trabeculae at central area and the lateral wall of the bony defects. The amount of new bone trabeculae confirmed the histological results. Conclusion: White Portland cement is a biocompatible osteoconductive economically affordable graft material and it id more efficient than β-tricalcium phosphate. (3476) Altaib Abdel Razik Mohammed, et al.

Introduction: The mammalian tongue displays significant morphological differences. These differences seemed to be related to the nature of food. Also, the surrounding environmental conditions play an important role in these differences. The dorsal mucosa of the tongue is covered by numerous papillae. In many mammals, tongue papillae play a vital role in food intake and digestion. The aim study: This study was to investigate the morphological characteristics of the circumvallate papillae (CVPs) of rat, dog, rabbit and goat. Materials and Methods: For this purpose, tongues of these animals were examined macroscopically as well as with light and scanning electron microscope (SEM). Results: Grossly observations reveled, in ratsa single large CVP surrounded by a semicircular moat and an indistinct annular pad. In dogs, five CVPs were arranged in two lines. The large papillae were surrounded by a wide moat and a prominent annular pad. Whereas, the small papilla lacked the annular pad and had irregular ridges.In rabbits, two CVPs enclosed by a deep moat lacking the annular pad. Whereas, goats had eight pairs of CVPs on both rims of the torus linguae and were encircled by a prominent gustatory moat and a thick annular pad. Histological examination of the four species revealed taste buds were located in the medial and lateral walls of the moat except for goats that had taste buds only in the medial wall of the moat. SEM examinationof the papillary surface exposedtransverse grooves in rats, irregular microridges and grooves in dogs and rabbits whereas the goats showed very little and small grooves. Conclusion: Hence, this study highlighted a variation in the morphology and microscopic anatomy of CVPsas an adaptation to their different feeding behaviours.

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Aims:The current research was performed to study histopathological, immunohistochemical and ultrastructural characteristics of gingival tissue in peri-implantitis.Methods & Results: This study examined 25 patients between ages of 30-40 years. Twenty patients were selected with peri-implantitis (peri-implantitis group) in which inflamed gingival tissues were surgically removed. The gingival soft tissue collars from five healthy patients with partially impacted third molar were surgically removed (control group). All gingival tissue samples were examined histologically and ultrastructurally. Immunoreactivity to CD3 and CD20 antibodies was also evaluated. Cases of peri-implantitis stained with hematoxylin and eosin demonstrated hyperplastic nonkeratinized epithelium with downward growth of rete ridges. Connective tissue stroma revealed prominent vascularity, proliferation of fibrous tissue and focally aggregated inflammatory cell infiltration localized to the subepithelial area. Immunohistochemical results exhibited large numbers of T (CD3+) and B (CD20+) lymphocytes in peri-implantitis compared to normal tissue with a statistically significant difference. All cases of peri-implantitis demonstrated no significant difference between T and B lymphocytes. Transmission electron microscope showed wide intercellular spaces with fine bundles of keratin intermediate filaments around the nucleus. Fibrous connective tissue stroma with active fibroblasts and numerous mixed inflammatory cells (plasma cells, mast cells and numerous activated lymphocytes) were also revealed. Conclusions:Variable histopathological changes appeared in peri-implantitis soft tissue including hyperplastic nonkeratinized epithelium, mixed inflammatory cell infiltration with no statistical difference between T and B lymphocytes, excessive collagenization and vascular proliferation. Understanding these histopathological alterations may help clinicians in better management of peri-implantitis condition to ensure longevity of dental implants.

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